Mamiya 6 has had issues with the collapsible mount for years and the GX680 needs a cart pulled along by a small pony for portability. Fujifilm GF670/CV Bessa 667 are now pushing $4k (and fragile). In contrast to 35mm camera, MF models were never made in large numbers (Hasselblad 500 series excepted) and supply will dwindle
Why do you assume MF cameras are rare or not made in large numbers?
Consider a camera like the Canon F-1, which is not a rare camera at all, yet a pro camera. Production figures are 380,000 (1971-1980).
source
All the post-war Rolleiflex f2.8 models sum over 175,000 cameras (
source)
Post-war Rolleiflex f3.5 sum easily over 400,000 cameras (
source)
The Bronica ETR system has sold over 300,000 cameras. Source? They had a "300,000" commemorative model. And this is a relatively "rare" camera compared to cameras like the Mamiya TLR series... You can assume the Mamiya TLR series easily sum one million, maybe more. I can bet there are 4 times the amount of Mamiya TLR cameras out there than Rolleiflexes. Easily.
Your argument makes sense to a point but in essence, every non-essential item is driven by trends. The P&S fad has been going on far longer than 2 years and hasn't let up either--been following it out of curiosity & the rise of Contax and Olympus P&S hasn't appreciably cooled.
Then, we agree.. And I think the P&S fad will end as the cameras break down, because as a camera repairman I tell you, most of those P&S break down quickly and are nigh impossible to repair. I'm already seeing this -- people write me with their broken P&S (mostly ones with autofocus zooms) for repair, cameras that they bought just months ago. Yes, this includes Olympus P&S like the Stylus series.
It's just a matter of time until people realize those are almost disposable cameras. As people did know back in the day.
I don't ever remember the Canon AE-1 as a 'hot item' nor the Pentax K1000; the latter rarely in demand outside college students taking a photography class.
Again, i'm not talking about 20 or 30 years ago, but i'm talking about years 2020-2021 and buying public = people 18-25 years old. Every Canon AE-1 i placed for sale, sold the very same day in a matter of hours. In fact i've a Canon AE-1 that i need to repair before putting it on sale and it already has 3 potential buyers waiting for it. Same for the K1000.